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Realization of large effective phonon magnetic moment in monolayer MoS$$_2$$ has established an important route for exploring intriguing magnetic phenomena in a nonmagnetic material. The sizable coupling between the orbital transition and the circularly polarized phonon results in the large effective phonon magnetic moment. In this work, using magneto-Raman spectroscopy, we investigate substitutional doping of magnetic atoms as a tuning knob of the electronic and phononic properties of MoS$$_2$$. We show that Fe-doping polarizes the spin of the conduction bands and introduces a localized Fe band underneath the conduction band. As a result, an additional orbital transition between the Mo 4$$d$$ and Fe 3$$d$$ states emerges, producing an orbital-phonon hybridized mode at 283 cm$$^{-1}$$. Our magnetic field dependent measurements demonstrate that this new mode carries 2.8 $$\mu_B$$ effective phonon magnetic moment, which is comparable to that of the undoped MoS$$_2$$. Moreover, even though a long-range magnetic order is absent in Fe-doped MoS$$_2$$, the local magnetic moment of Fe modifies the nature of the spin fluctuation, producing monotonically increasing quasielastic scattering spectral weight as temperature decreases. Our results highlight two-dimensional dilute magnetic semiconductors synthesized by substitutional doping as a promising material platform to manipulate the phonon magnetic moment through orbital-phonon coupling.
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Donor-acceptor pairs in wide-bandgap semiconductors for quantum technology applications
Abstract We propose a quantum science platform utilizing the dipole-dipole coupling between donor-acceptor pairs (DAPs) in wide bandgap semiconductors to realize optically controllable, long-range interactions between defects in the solid state. We carry out calculations based on density functional theory (DFT) to investigate the electronic structure and interactions of DAPs formed by various substitutional point-defects in diamond and silicon carbide (SiC). We determine the most stable charge states and evaluate zero phonon lines using constrained DFT and compare our results with those of simple donor-acceptor pair (DAP) models. We show that polarization differences between ground and excited states lead to unusually large electric dipole moments for several DAPs in diamond and SiC. We predict photoluminescence spectra for selected substitutional atoms and show that while B-N pairs in diamond are challenging to control due to their large electron-phonon coupling, DAPs in SiC, especially Al-N pairs, are suitable candidates to realize long-range optically controllable interactions.
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- PAR ID:
- 10484562
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- npj Computational Materials
- Volume:
- 10
- Issue:
- 1
- ISSN:
- 2057-3960
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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